BUGFIX: Using Dovecot with MDBOX format of mailbox, if you delete a box with one or more sub-boxes, the dovecot can't remove the dir of parent box.

PROBLEM: Using Dovecot with MDBOX format of mailbox, if you delete a folder with one or more sub-folders, the dovecot can't remove the dir of parent folder.

If the back-end use dovecot with MAILDIR, the DELETE action in mailbox, remove the parent and all children folders because the structure of files and folders is different of MDBOX ( I dont see the code, but I should look like a "rm -rf" on folder).

MAILDIR:

parent_folder
  |_cur
  |_new
  |_tmp
  |_child-folder
               |_cur
               |_new
               |_tmp
 
MDBOX:

parent-folder
   |_dirs_boxes
   |_child-folder
             |_dirs_boxes

To fix in roundcube:
I change the order of DELETE Boxes, first the remove the children folders after remove parent folder.